LAUS Upper Limb 22-23 with answers (1).docx
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BSMS MODULE: 204 – THE MUSCULOSKELETAL AND IMMUNE SYSTEMS THEME 2: THE MUSCULOSKELETAL SYSTEM LIVING ANATOMY – THE UPPER LIMB In this living anatomy session, you will study the joints, muscles and movements of the upper limb, as well as use ultrasound to examine the upper limb. Learning Outcomes By...
BSMS MODULE: 204 – THE MUSCULOSKELETAL AND IMMUNE SYSTEMS THEME 2: THE MUSCULOSKELETAL SYSTEM LIVING ANATOMY – THE UPPER LIMB In this living anatomy session, you will study the joints, muscles and movements of the upper limb, as well as use ultrasound to examine the upper limb. Learning Outcomes By the end of the session, you should be able to: Identify the skeletal components of the shoulder, arm, forearm and hand Describe the range of movements for each of the joints of the upper limb Determine simple tests that can be used to assess muscle function in the clinic Identify the borders of the anatomical snuff box Identify the muscles, vessels and nerves of the upper limb on ultrasound Task 1: Examination of the joints, muscles and movements Each of the tasks can be performed either on a volunteer or yourself. Shoulder and arm At the medial end of the clavicle, palpate the sternoclavicular joint, which is a synovial saddle-shaped joint. Palpate this joint while moving the shoulder and arm. Q1. Which limb movements cause rotation at the sternoclavicular joint? Since this is a saddle joint, most movements will cause rotation at this joint. For example: abduction, adduction, flexion and extension of the arm, as well as elevation, depression, protraction and retraction of the scapula. At the lateral end of the clavicle, palpate the acromioclavicular joint, which is a plane type of synovial joint. To appreciate movement at this joint, try abducting your arm above your head. Q2. In a dislocation of the acromioclavicular joint, which of the two bones would lie uppermost? The clavicle usually lies uppermost because the most frequent cause of dislocation of this joint is a direct blow to the acromion/fall onto the point of the shoulder (e.g. during contact sports such as rugby). This frequently leads to both rupture of the acromioclavicular and coracoclavicular ligaments, the latter of which leads to elevation of the clavicle. Now, palpate the acromion and coracoid process. The coracoid process lies inferior to the lateral end of the clavicle. The glenohumeral joint is a ball and socket joint that can perform a wide range of movements. Perform all of the movements possible at the glenohumeral joint. Q3. How would you test (a) lateral and (b) medial rotation at the glenohumeral joint? The action of placing the hand behind the head is a good test of lateral rotation. Actively placing the hand on the back between the scapulae tests medial rotation. With the arm abducted to 90° and the elbow flexed to 90°, moving the forearm upwards and downwards tests lateral and medial rotation respectively. Movements of the scapula change the position of the glenohumeral joint, which helps to extend the reach of the hand. Reach out in different directions with your hand. Q4. What movements can the scapula perform to increase the reach of the hand? Elevation, depression, protraction, retraction and rotation (during abduction and adduction of the arm). Q5. Can you devise a simple clinical test for assessing the function of deltoid? Ask the person to abduct their glenohumeral joint against resistance. Q6. Which nerve are you testing by asking a patient to perform this movement? Axillary nerve Forearm The elbow joint is a hinge type of synovial joint that is formed by the distal end of the humerus articulating with the head of the radius and the proximal end of the ulna. Perform the movements possible at this joint. Q7. What muscles cause flexion at the elbow joint? Biceps and Brachialis What muscle performs flexion at the elbow joint in the half-pronated position? Brachioradialis The proximal radioulnar joint is a type of pivot joint between the head of the radius and the radial notch on the ulna. On the posterolateral side of the elbow, locate and palpate the head of the radius. With the forearm extended, its position is indicated by a depression in the skin that can be observed between the bulge formed by the brachioradialis muscle and the olecranon. Examine the movement of the radius during pronation and supination of the forearm. Q8. What is the position of the radius in relation to the ulna when the forearm is supinated and pronated? Radius and ulna lie parallel to each other when supinated. The radius crosses over the ulna when pronated. Hand The wrist (radiocarpal) joint is a condyloid type of synovial joint formed mainly between the distal end of the radius and the scaphoid, lunate and triquetrium carpal bones. Perform the movements possible at the wrist joint. Q9. What movements can you perform at the wrist joint? Flexion, extension, abduction, adduction, circumduction The carpometacarpal joints between the distal row of carpal bones and the metacarpals have limited movement, except for the articulation between the trapezium and the first metacarpal. This joint is a saddle joint. Perform the movements at this saddle joint. Q10. What movements can you perform at the joint between the trapezium and the first metacarpal? Flexion, extension, abduction, adduction, circumduction, opposition and reposition The articulation between the trapezium and first metacarpal allows us to achieve precision grip (i.e. holding a pen), which is adaptable to a wide variety of differently shaped and sized objects. Perform a precision grip. Q11. Comment on the position of the wrist joint and the joints of the hand in a precision grip. In a precision grip, the wrist joint is neutral position or slightly extended. The metacarpophalangeal joints are flexed, and the interphalangeal joints (partly) extended. The wrist is held stable by the long flexor and extensor muscles. The intrinsic muscles of the hand (i.e. the lumbricals) flex the metacarpophalangeal joints and extend the interphalangeal joints. With the thumb extended (e.g. a ‘thumbs up’), palpate the tendons that form the borders of the anatomical snuff box. Q13. What are the names of the tendons that form the borders of the anatomical snuff box? Extensor pollicis longus, extensor pollicis brevis and abductor pollicis longus Within the anatomical snuff box, palpate the scaphoid bone. The metacarpophalangeal joints between the metacarpals and proximal phalanges are condylar joints. Perform the movements at the metacarpophalangeal joints. Q14. What movements can you perform at the metacarpophalangeal joints? Flexion, extension, abduction and adduction On the dorsal side of the hand, identify and palpate the dorsal interossei muscles. The easiest muscle to palpate is the first dorsal interossei, which is between the thumb and second metacarpal. Move your fingers to establish the action of the dorsal interossei. The palmar interossei cannot be palpated. Q15. Can you devise a simple bedside clinical test to assess the integrity of the palmar interossei? The palmar interossei adduct the digits. Ask your patient to hold a piece of paper between their second and third digit. Try pulling the paper away to assess the strength of adduction. The interphalangeal joints are hinge joints that flex and extend the digits. Perform the movements at the interphalangeal joints. On the dorsal side of the hand, locate the tendons of the extensor digitorum muscle as they pass to their insertions on digits 2–5. These are best palpated with the digits extended. The flexor tendons to the digits cannot easily be identified in the hand. Q16. What bedside clinical test would you use to assess the integrity of the flexor digitorum profundus tendons? The flexor digitorum profundus tendons insert into the distal phalanges of digits 2-5. Ask your patient to place their hand palm up on a table and flex the tip of each digit in turn. To test the muscle strength, use your fingers to resist the movement. Try performing this test on yourself. Task 2: Ultrasound imaging of the upper limb Ultrasound is frequently used in musculoskeletal clinics. It is used to identify muscle, tendon or ligament damage, bursitis, joint effusion (increased intra-articular fluid), vascular pathology, haematomas, abscesses, oedema and masses such as ganglion cysts or lipomas. It is also used as guidance for injections, aspiration or biopsy. As part of point of care ultrasound (POCUS), it is used to map upper limb veins for vascular access. Specific examples of clinical conditions that can be diagnosed by ultrasound, as well as procedures that utilise ultrasound, have been given for each region. For this task, you will use ultrasound to examine the muscles, nerves and vessels of the upper limb. Whilst imaging the muscles, ask the subject to move different joints to work out which muscles you are looking at. IMAGING THE SHOULDER Rotator cuff muscles Refer to page 110-111 in Gray’s Surface Anatomy and Ultrasound. Imaging is performed with the subject sitting facing the operator. Position the arm behind the back (i.e. in a medially rotated position). Place the probe over the glenohumeral joint in the position indicated on the diagram below. Attempt to reproduce the ultrasound image below. Identify the supraspinatus muscle and tendon. Examine the supraspinatus muscle during abduction of the arm. IMAGING THE ARM Refer to page 113-115 in Gray’s Surface Anatomy and Ultrasound. Imaging is performed with the subject sitting, facing the operator. The arm should be abducted to 30–40 degrees, or laterally rotated, so that the medial side can be more easily imaged. It may be more comfortable to rest the elbow on a table. Place the probe over the medial arm in the position indicated on the diagram below. Attempt to reproduce the ultrasound image below. Identify the brachial artery and veins, basilic vein, median nerve, and biceps and brachialis muscles. IMAGING THE FOREARM Elbow joint Refer to page 115-118 in Gray’s Surface Anatomy and Ultrasound or PowerPoint. Imaging is best performed either sitting or lying prone, with the elbow extended and forearm supinated. Place the probe over the elbow joint in the position indicated on the diagram below. Attempt to reproduce the ultrasound image below. Identify the capitulum, head of the radius, common extensor origin muscles, brachialis and brachioradialis muscles. Examine these structures during movement of the elbow joint. Anterior forearm and carpal tunnel Refer to page 118-121 in Gray’s Surface Anatomy and Ultrasound or PowerPoint. Imaging is best performed with the subject sitting, facing the operator, elbow flexed to 90 degrees, forearm supinated and resting on a table. Place the probe over the anterior forearm in the position indicated on the diagram below. Attempt to reproduce the top ultrasound image below. Identify the flexor carpi radialis, flexor digitorum superficialis, flexor digitorum profundus and pronator quadratus muscles. Examine these muscles during movements of the digits and wrist. Trace the median nerve, radial and ulnar arteries distally. Examine the contents of the carpal tunnel as shown in the bottom ultrasound image below.
